1. Field of the Invention
The present invention relates to an image processing technique capable of blurring an image captured by an imaging apparatus with a solid-state image sensor.
2. Description of the Related Art
Conventionally, a dioramic shooting that captures an image including upper and lower blurred areas has been optically realized. An optical element capable of realizing the dioramic shooting is, for example, a special lens such as a tilt-shift lens that can be used to perform bird's-eye view shooting. Further, performing image processing on a captured image is useful to realize various blurring effects including dioramic effects. Japanese Patent Application Laid-Open No. 2000-69277 discusses a technique for mixing an ordinarily captured image (original image) with a blurred image derived from the original image at an appropriate ratio to obtain a soft focus effect. Further, as discussed in Japanese Patent Application Laid-Open No. 2004-102904, sequentially performing reduction, filtering, and enlargement processing on an ordinarily captured image is useful to acquire an appropriate blurred image.
However, when the image processing is employed to realize a high-quality dioramic still image, it is usual that blurring processing is performed by changing the degree of blur at a plurality of stages. On the other hand, display of dioramic images may be required when a live image is displayed during preparation for a still image shooting operation or when recording of moving images is performed. In this case, the image processing is performed in such a way as to realize real-time generation of dioramic images for numerous frames. Accordingly, if acquiring dioramic images appropriately in various shooting conditions is required, a processing speed tends to decrease and usage of a memory or other resources is restricted while high-quality images are required.